1. Field of the Invention
The present invention relates to the construction of two mating sliding parts in a linear feeding means. More particularly this invention concerns a linear feeding assembly, wherein a carriage member is supported on or around a linear supporting member and these two members are relatively and slidably movable in the lengthwise direction of the supporting member. A number of recesses of arrow head patterns for generating hydrodynamic pressure are arrayed on either one of or both of the sliding faces in the direction of movement, such that the arrow heads are directed both normal and reverse to the direction of movement, to generate hydrodynamic pressure in both directions, for assuring smooth movement in both directions.
2. Description of the Prior Art
The construction of the two mating sliding members of a conventional linear feeding means has been of the type wherein a carriage member is attached on or around the sliding face of the rod-shaped supporting member used for slidable movement. Particularly, in linear feeding means for feeding a carriage of a printer which is one of the office automation apparatuses required to repeat very rapid reciprocal movement, the manner of lubrication has been accomplished by applying a sufficient amount of lubricant to the sliding surfaces. In many cases, a major part of the sliding face of the rod shaped supporting member has been exposed outside the area of mutual fit with the carriage member, and most of the lubricant has been applied to the exposed portion with the accompanying liable chance of contaminating the interior of the device. Thus, it has long been desired to apply a minimum amount of lubricant to keep the interior of the device clean. For this purpose, it is also desired to attain satisfactory lubrication with as small an amount of lubricant as possible.
As explained herein before, since the linear feeding means comprises a long rod-shaped carriage member, a major part of which is exposed outside the mutual fit with the carriage member, it has been difficult to obtain satisfactory lubrication unless large amounts of lubricant is applied thereto.
In view of these problems, the inventors have accomplished the present invention. Prior art devices known to the inventors are disclosed in U.S. Pat. No. 4,141,603 and Japanese Utility Model Laid-Open Publication No. 54-150044 both relating to bearings.
Since these prior art devices are either a journal bearing which does not move in its axial direction or a thrust bearing in which the bearing surface is not exposed and thus the lubricant applied therein is not exposed, there has been almost no fear of contamination of the applied lubricant. In addition, it has not been required to apply lubricant in large amounts. Accordingly, these prior art devices are not relevant to the subject matter of the present invention.
As mentioned above, the present invention aims to solve such pending problems in linear feeding devices. It is therefore an object of the present invention to depress the working noise and friction between two mating sliding faces. Another object of the present invention is to provide a novel construction of the mating slide faces of the linear feeding means which functions smoothly over an entire operating range with no lubricant at all or with very small amounts of lubricant. A further object of the invention is to provide novel mating slide faces of the linear feeding means which can secure the necessary and sufficient amount of lubricant.